Theater lighting control apparatus



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THEATER LIGHTING CONTROL APPARATUS Original Filed Sept. 10, 1932 l2 Sheets-Shaei 10 12 Sheets-Sheet l1 B S BURKE THEATER LIGHTING CONTROL APPARATUS Original Filed Sept. l0, 1952 3B 2kb NVENTOR March 4, 1941.

THEATER LIGHTING CONTROL APPARATUS B. s. BURKE 2,233,808

Urgnal Filed Sept. l0, 1932 l2 Sheets-Sheet 12 Patented Mar. 4, 1941 uNrrED STATES PATENT oFFicE THEATER LIGHTING CONTROL APPARATUS Burt S. Burke, Webster Groves, Mo., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Original application September 10, 1932, Serial No. 632,558. Divided and this application April 19, 1938, Serial No. 202,977

7 Claims.

' trol apparatus for theater lighting and like circuits wherein facilities are provided for selectively presetting the lighting characteristics of a plurality of circuits for a number of effects or scenes in advance, and wherein different groups of lighting circuits may be energized predetermined degrees during the selected scenes, and wherein the lighting intensities of the different circuits may be simultaneously varied proportionately from a predetermined intensity to any desired intensity of illumination.

Another object of the invention is to lprovide a control system for theater lighting and like circuits wherein each circuit contains a plurality of presettable current controlling elements4 that may be selectively connected in the circuit and wherein a plurality of individual control elements are provided each of which may control the said controlling elements of any desired number of selected circuits.

Another object of the invention is to provide a control system for theater lighting and like circuits wherein the said individual control elements may` be yactuated individually to vary the light intensity of the circuits thenassociated therewith, or may be preset to eiiect predetermined light intensities in the Said circuits, and wherein the said individual control elements are divided into sub-groups and influenced simultaneously by a sub-group control element.

A further object of the invention is to provide a control system for theater lighting and like circuits wherein the individual lighting circuits may be r1) selectively placed under the influence of an individual control element in selected groups,

2 or placed under the inuence of a subgroup control element in selected group of groups, or

i3) selectively and collectively in groups of any number placed under the influence of one of a group of group master control elements which iti turn may be influenced simultaneously through a voltage control element such ,as a grand master potentiometer for controlling the field oi the generator supplying the control current.

A further object of the invention is to provide a control system for theater lighting or like cir- (Cl. V75-312) cuits having the above-noted characteristics wherein the lighting circuits are controlled through the medium of a reactor and wherein the control apparatus affects the voltage of a grid circuit of a vacuum tube, the output of which is impressed upon the control winding of the reactor.

A further object of the invention is to provide a control system for theater lighting or like circuits wherein the control elements may be compactly arranged in such manner as .to render them accessible to an operator who may be seated at a point remote from the stage, and

wherein the control elements are arranged in a console similar to that of a pipe organ, and wherein'the various control elements may be actuated selectively and individually eithermanually through nger operated keys, in group through foot pedals or hand operated wheels, or automatically at selected speeds through the medium of motor driven elements under the control of the operator.

A -further object of the invention is to provide a control system for theater lighting or like circuits that is capable of producing a great variety of lighting effects which may be selectively pre-arranged and ultimated at predetermined times, and wherein an endless variety of colors and hues may be attained by proportoning the intensities of the lighting in circuits having the primary colors, and. wherein a color composed of the combined colors of several circuits may be maintained without change of hue while being reduced or increased in intensity.

These and other objects that will be made apparent throughout the further description of the invention are attained by means of the control apparatus hereinafter described and illustrated in the accompanying drawings, wherein Figure 1 is a wiring diagram showing a portion of representative circuits wherein features of the invention are embodied,

Fig. 2 is a wiring diagram showing a continuation of the circuits illustrated in Fig. 1,

Fig. 3 is a wiring diagram illustrating the wiring connections 'to the master potentiometer clutches,

Fig. 4 is a front elevation of a console ,upon which the control apparatus is mounted,

Fig. 5 is a vertical section through the console taken on the line V'-V of Fig. 4,

Fig. 6 is a top plan view of a portionof the operating mechanism for actuating the master potentiometer and feeders,

Fig. 7 is a vertical section through the apparatus shown in Fig. 6 and additional apparatus, taken on the line VII-VII of Fig. 6,

Fig. 8 is a plan view of the apparatus shown in Fig. 7, showing a portion of the apparatus below the line XIII-XIII thereof.

Figs. 9 and 10 are projected front plan views of the instruments located on the front panels of the console, the instruments shown in Fig. 9 being disposed above those shown in Fig. 10,

Figs. 11 and 12 are vertical sections through the portion of the console having the instruments disclosed in Figs. 9 and 10 taken respectively on the lines Xl--XI and XII-XII thereof.

Referring to the drawings, the apparatus will best be described by reference to the wiring diagrams illustrated in Figs. l and 2 wherein a plurality of circuits are represented, the first and last of the series being represented in full on the left and right sides of the iigures respectively, and the intermediate circuits being represented by rectangles in dash and dot lines.

Beginning at the bottom of the diagram on Fig. 2, the number I lamp or lighting circuit at the left side of the figure will be referred to specifically, it being understood that each circuit of the group is provided with similar control apparatus, and that any desired number of lighting circuits may be provided and controlled in the manner hereinafter specified. The various circuits may be lprovided with lamps of diiferent color, preferably white and the three primary colors, red, blue and yellow, thus the footlights would comprise four circuits each having lamps of a color different from those of the remaining circuits of the group.

All of these lighting circuits No. 1 to No. 100, for example, comprise lamp circuits I3 that are supplied with current from supply feed conductors I4 and Il through the medium of a saturated core reactor I6, having a direct current control winding I1 that influences the reactance of the reactor to vary .the voltage of the lamp circuit in response to iluctuations of the current through the control winding in a well known manner.

The current supplied to the control winding ci' the reactor is controlled by a current control unit Il such as is disclosed in the United States Letters Patent No. 2,030,801, granted to Robert D. Ross on February 11, 1936, and assigned to the assignee oi' this application and which comprises a three-electrode vacuum tube so assoelated with amplier tubes that variations of the grid potential of the three-electrode tube causes corresponding variations in the output circuit of the amplifier tubes that is connected to the control winding I'I of the reactor through conductors Il and 2|.

In the diagrams the grid conductor that is connected to the grid of the three-electrode tube is designated'by the numeral 22 and the positive and negative control circuit conductors are designated by the numerals 23 and 24, respectively, which are connected to .the main direct-current generator 25, indicated at the top of'Fig. 1.

In the control system illustrated, there are provided one hundred circuits each of which is provided with a grid circuit conductor- 22, and

. there are thirty-six control units for controlling the various grid circuits. Facilities, to be hereinafter described, are provided for selectively placing any, desired number of grid circuits under the influence of a selected control circuit, and in the present instance any eight circuits may thus be combined cr grouped under the control of a single control unit.

Included in each lighting circuit control are thirty-six grid circuit relays 261, 2li2 etc. of the over-center spring-held type having two operative positions, namely closed position wherein two contacts W and V are closed and contacts X, Y and Z are opened, and released position wherein contacts 'W and V are opened and contacts X, Y and Z are closed. Each relay is provided with an actuating coil 2l.

Each of the thirty-six control units includes a normally open multi-contact relay 23 having an actuating coil 25 and a. contact-supporting rod 3l having a pair of contact bars 32 and 33 for each of the one hundred circuits. When the coil is energized by momentarily closing of a cross connecting push button switch 341, 342, 3431 asso ciated with their respective control units, thc

contact bars 32 and 33 engage their respective contacts 32a and 32h connected in the circuit containing the grid circuit relay coil 21 and will cause that coil to actuate the grid circuit relay, provided that the circuit is otherwise completed. Whether it is completed will depend on factors of control to be hereinafter described. On a panelboard hereinafter referred to as a crossM connecting panel, are mounted cross-connecting circuit switches 35, one for each circuit and designated specically as 391, 392, 39100. The switches are of the single-pole double-throw type having its pivoted blade connected to the negative con-trol feed conductor 24 and adapted to alternatively be moved to closed or released positions wherein it engages the contacts 4i and 42 that are respectively connected `to contacts 1I of the grid circuit relay and one of the con tacts 32h of 4the multi-contact :relay 28.

It will be understood that thegrid conductor 22 connected to the grid ci" the three-electrode tube oi the control unit IB may be connected through a variety of control devices interposed between the negative terminal 43 of the generator 25 and the grid terminal of the control unit IB for the purpose of placing the control of the circuit under the control of different control mechanisms that may function in a variety ci combinations or which may be manually or motor operated at different speeds, individually or collectively in predetermined groups.

In order to divide the controlled lighting cira cuits into groups and to place the grid circuits oi the selected lighting circuits under the control of any one of the thirty-six control units, say control No. 1 for example, the cross-connecting circuit switches 391, 3911, 3811, 3915 etc. are moved to closed position. Therefore, the grid circuits of lighting circuits No. 1, 6, 12 and 16 are -prcpared for simultaneous energization as a group under the control of the cross-connectingpush button 341. At this time, it is assumed that the contacts W and V ci the grid circuit relays 261 of each of the selected circuits are closed and the contacts "X, Y and Z open. The grid conductor 22 is then connected to the negative ieed conductor 24 through series connected contacts V of all of the grid circuit relays 261 to 2636.

When the cross-connecting push-button switch 341 for control unit No. l is momentarily closed, the coil 29 is energized and the normally-open multi-contact bars 32 and 23 of each of the one hundred circuits to engage their respective contacts. This action causes energization oi the grid circuit relay coil 2'I through the contact bars 32 which causes all of the relays 26' of the selected circuits associated with the control No. 1 relay 2B to operate and open contacts W and V ill) fi D

thereof, the circuit from the positive control feed conductor 23 being through contact bar 32, contact 32a, coil 21, conductor 45, common to the .thirty-six relays of the circuit, conductor 46,

contact V of relay 2616 and all of the remaining relays and nally through contact 4I and the closed cross-connecting switch 39' to the negative control conductor 24.

Energization of the coils 21 of the No. I control units of the selected circuits of the group, as stated above, then opens contacts W and V and closes contacts X, Y and Z of the grid circuit relays. Since the contact V of the relay 26 is then open, subsequent'movement of the crossconnecting circuit switches 39 of circuits not originally selected for control unit No. I cannot be added to the selected group 'without again momentarily closing the cross-connecting push button switch 34'.

Since the contact V of the grid-circuit relay 26 is open, the selected circuit cannot at the same time be controlled through any other control unit such a3 No. 2 or No. 36, because the coil 21 of such relays cannot be energized so long as any one of the series related contacts V are open.

To again close the contacts W and V the switches 39' etc. are moved to release position and when the switch 34' is again momentarily closed, a circuit is established through the coil 21 through bus 241, connected to the negative control conductor 24, switch 39', contact 42, bus 422 common to the 36 relays 26' to 2635, contacts 521 and bar 33, conductor 338, contact X, coil 21, contacts 32a and bar 32, bus 23a to positive control conductor 23.

When the contact W is opened the grid circuit is transferred from contact W to Contact Z, that is, connected to the bus 31' that is connected in common to all of the contacts Z of the grid circuit relays 261 ofthe No. I control unit. The busses 41 to 4138 are connected respectively to second busses 48' to 4336 that are connected respectively to one arm 49 of a double-pole doublen throw pilot switches I1 to 5I31 (one for each control circuit means) that is movable to on and oi positions. When this switch is in the off position shown, the grid conductors ofthe associated circuits remains connected to the negative conductor 24 and cannot 'be inuenced through other controls such as the potentiometers to be hereinafter described.

When the pilot switch 5I1, for example, isin the on position the grid conductor is connected to the pivoted arm of a singlepole double-throw selector switch 52' through conductor 53 and which is alternatively movable to manual and pre-set positions. At this time the switch arm 54 closes a circuit through a pilot lamp 6 0 thus indicating that the circuit is now ready for operation.

With the selector switch 521 in the manual position the grid circuit includes a conductor 55 that is connected to a movable contact 56 of one of thirty-six individual control potentiometers 511, 512, 5135, one end of which is connectedto a common negative bus 58 that is connected to the negative control conductor 24 and the other end of each bein-g connected to the moving arm of a sub-group of selector switches `591, 592, 593, 594, 595, etc. The negative bias on the grid circuit at this time is determined by the position of the arm on the potentiometer, assuming that the upper end of the potentiometers 511, 512 are connected to the positive conductor 23 through circuits including the switches 591, 592, etc.

With the selector switch 521 in the pre-set position the grid circuit is connected through conductor 6I to protective resistor 62 to normally open relay contacts 63, 64, 65 and 66 of scene flasher relays 61, 68, 69 and 10, respectively, and to the normally closed contact 1I of the fader disconnect relay 12. The actuating coils of the relays 61, 68, 69 and 10 are connected across the positive and negative control conductors 23 and 24 respectively, through the medium of push and pull scene asher button switches 13, 14, and 16, respectively, and the coil of the normally energized relay 12 is energized through a series of normally closed break contacts 11 connected in series relation and actuated severally by the relays 61 to 16 to open position when any of the said relays are actuated to close the contacts 63, 64, 65 and 66.

'I'he contacts 63, 64, 65 and 66 are connected respectively to four points 63', 64', 65' and 66', respectively, of a scene fader potentiometer 18, and respectively to the movable contacts 63", 64", 65" and 66" of four pre-set potentiometers 19, 80, 8l and 82. The contact arm 83 of the scene fader potentiometer 18 is connected to the protective resistors 62 through the medium of the contact 1 I.

Thus it will be seen that when the selector switch 52 is in the pre-set position the grid circuit is connected through,

11) A preventive resistor 62, contact 1I of the fader disconnect relay 12, to the moving arm 83 of the scene fader potentiometer 18.

t 2) Preventive resistors 62 and contacts 63 of scene flasher relay 61 for scene I, 68 for scene II. 69 for scene III and 16 for scene IV.

It will be understood that the relays 61 to 10 and 12 comprise bars 84 that are actuated by the coils of the relays 'and are connected to the contacts 63 to 66, 11 and 1I, so-that said contacts of all circuits are actuated simultaneously by the bars 84.

The function of the scene fader is to accomplish a gradual and proportional transition from one scene to the next succeeding scene. This is accomplished as follows.

With the grid wire connected to the `moving arm 83 of the scene fader potentiometer 18, and this arm on position 63' for scene I, a negative potential is applied to the grid circuit depending upon the position of the movable arm 63" of pre-set potentiometer 19 for scene I, the lower end of which is connected to the negative control feed conductor 24.

`Moving the arm of the scene fader from position 63' (scene I) to the position 64' (scene 2) gradually changes the potential impressed on the grid circuit from that previously set up on pre-set potentiometer 19 i scene I) to that pre-set on potentiometer 80 i scene 2) Assuming operation on scene I and that itis desired'to transfer instantly to the scene 3 operation, upon depressing the scene flasher push button 15 which energizes the ccil of the relay 69, the contact 65 thereof is instantly connected to the moving arm 65" of the potentiometer 8I (scene 3) and the Contact 11 of that relay opened,

thus interrupting the circuit through it to open its contacts 1I. This last operation disconnects the grid wire from the moving arm of the fader leaving it connected through the scene flasher relay contacts 65 of the relay 69 (scene 3).

To restore operation of the fader, scene flasher button is pulled out, thus deenergizing the scene flasher relay 69 (scene 3) and disconnecting the grid wire from the moving arm 65" of pre-set potentiometer 8| (scene 3), at the same time closing the break contact 11 of that relair thus completing the circuit through the operating coil of the fader disconnect relay, causing it to close its contacts, thus again connecting the grid wire to the moving contact 53" of pre-set potentiometer 19.

To flash from scene 3 to scene 4 pre-sets without utilizing the fader, depress scene flasher pushbutton 16 (scene 4) and pull the previously closed pushbutton 15 (scene 3). This operation closes scene flasher relay 10 and connects the grid conductor to the moving arm 66' of the pre-set potentiometer 82, and disconnects it from the potentiometer 81 (scene 3).

It will be understood that the resistance ci the scene fader potentiometer 18 is Suiiiciently light to allow changing the pre-set potentiometers of the scenes not in use without eiecting a change in the scene in progress.

So far, it has been shown in what manner any number of circuits may be placed under the control of one of the thirty-six control units and the manner in which the light intensity of the selected circuits may be pre-set for 'four scenes and the manner in which the control units may be individually operated at will to vary the negative grid potential on the tube control units to produce desired light intensity variations,

It will now be shown how the thirty-six control units may be operated individually or in groups of four through any one of nine sub-group potentiometers or how any number of control units may be controlled through any one of iour Ygroup master potentiometers, or in what manner any one or all of the four group master potentiometers may be controlled by a grand man ter potentiometer which controls the generator voltage of the control circuit.

The manner in which the circuits are to be controlled is primarily dependent upon an interlocking selector switch 85 shown in Figs. l1) and 11 (one for each of the thirty-six control units) the switch comprising an individual switch 86, a grand master" switch 81 and four group master switches 881, 082, 883, 984. Each switch includes a normally open contact 89 and a normally closed contact 81, the latter. contact oi all of the switches being connected in series relation.

The construction of the interlocking switch 85 is such that when a control button of any switch 881, 8B1 etc. is pushed in to close its respective normally open contact 89 and open its respective normally closed contact 91, any other button that is then in the in position will be forced out to its original position. It will be seen, therefore, that a circuit can be influenced by one only of the above referred to control devices at any one time.

It will vbe understood that the sub-group se lector switches 591, 592, etc., the movable con tacts of which are connected to the positive end of the individual potentiometers 511 and 512 etc., respectively, are normally in the on or closed position wherein the positive ends of the individual potentiometers are connected to their respective interlocking switches 85 through conductors 92.

To obtain control of the circuits connected to a selected individual potentiometer, as for example, 511 the button of its respective individual switch 86 is depressed opening contact 9| and closing contact 89.

The potentiometer 511 is then connected across the negative and positive control conductors through negative control bus 58, potentiometer 511, closed switch 591, conductor 92, contact 89 to the positive individual bus 93. The negative bias on the grid control conductor 55 is then dependent upon the position of the movable contact 59 on the potentiometer 511. Ii the contact 56 is at the negative end of the potentiometer, the negative bias is maximum and the lamps of the lighting circuits are black out. The degree of illumination will thereore be dependent upon the position of the contact 56 and full illumination of the lamps of the lighting circuits will be obtained when the contact 55 is near the positive end of the potentiometer 511.

Should it be desired to place selected individual control potentiometers 511, 512, etc., under the iniiuence of any one ci four' group master potentiometers 941, 942, 943, or 941,'or example, 941, the button of the group master switch 88 of each selected control potentiometer is depressed, closing the contact 99 thereof and opening the contact 91. This action automatically returns the individual switch 86 to its original "outi position. "Under thiscondition, the positive ends ci the selected potentiometers are connectecl to the positive control conductor 23 through the following circuits, conductor `92, contacts 91 of interlocking switches B8 and B1, contact 89 of switch 88', group master bus 95', conductor 98', movable contact 91', groupmaster potentiometer 94', normally open groupinaster switch 98', which when closed connects the positive end of the potentiometer 94 to the positive bus 99 connected to positive control conductor 23.

Thus all or any of the 36 potentiometers 511, 512, etc., may be connected to and controlled by any one of the four group master potentiometers 941, 942, 943 or 944 when its respective group master switch is in the closed or individual position, wherein the positive end of the poten tiometer is connected to the positive bus 99.

The four "group master potentiometers 941, 942, etc., may be selectively or collectively controlled by a grand master potentiometer |01 that is connected across the positive and negative control conductors 23 and 24, respectively, by moving the group master switches 981, 992, 983 and 984 to the master position wherein the 1 positive ends of the group master potentiometers 941, 942, etc.. are connected to a bus 102 that is connected to the positive grand-master generator bus |03. The bus 103 is connected to the positive terminal |04 of the grand master generator 105 and potentiometers 941, 942, etc., are connected to a bus 102 that is connected to the positive grand-master generator bus |03. The bus |03 is connected to the positive terminal 104 of the grand master generator 105 through bridging contact 106 of a black-out" contacter switch |01. A movable contact |08 connected to the field winding 109 of the generator |05, slidably engages the potentiometer coil 101 and determines the voltage output of the generator 105, thus effecting the negative bias of the grid wires 55 that are then controlled through individual control potentiometers 511, 512, etc., and group master potentiometers 941, 941, etc.

The individual control potentiometers 511, 5111,

etc., may be grouped in groups of four each and thus selectively or collectively controlled in groups of four through one of nine sub-group potentiometers |||1, |||2, H33, etc., by connecting the positive ends of the potentiometers of 511, 512, 513 and 51*1 to potentiometer ||i1, potentiometers 515, 516, 51'I and 518 to potentiometer |||2, etc. This is done by moving the sub-group selector switches 591, 592, etc., oi desired control potentiometers 511, 512, etc., to the sub position, or from the normal interlock position shown in Fig. 1 to the left hand position wherein the positive ends of the potentiometers 511, 512,

etc., are connected to the through conductors ||2 to the movable contacts ||31, H32, etc., that slidably engage the sub-group potentiometers |||1, |||2, etc., respectively, having their negative ends commonly connected to the negative bus ||4 that is connected to negative control conductor 24, and having their positive ends connected to pivotal sub-group potentiometer or to switches ||51, H52, H53, etc., that may be moved by the foot of the operator to connect the potentiometers direct to the positive bus ||6 that is in turn connected to the positive feed conductor 23, or to a bus ||1 that is connected to the positive generator bus |03,

When the potentiometers are connected to the positive conductor 23 as in the first-mentioned instance, the grid control Wire 55 is controlled through the individual potentiometers 511, 512, etc., and the sub-group potentiometers ||31, I |32, etc., and when the individual potentiometers are connected to the positive generator bus |03, the control is extended to the "grand master generator |05 which effects changes in voltage in the positive conductor dependent upon the position of the moving contact |08 of the grandmaster potentiometer which controls the field winding of the generator,

Thus it will be seen that the lighting circuits are controlled by the negative bias imposed on a grid wire of a three-electrode tube which in turn controls an A. C. amplifier which rectifies its output and controls a saturated core reactor.

The negative bias of any number of grid wires may be placed under the control of any one of thirty-six control potentiometers, and the potential across these potentiometers may be selectively varied either through sub-group potentiometers or group `master potentiometers, selectively supplied with current from either of two generators, one of which, the generator |05, effects variations in potential through potentiometer control of the field winding and the other, generator 25, effects variations in potential supplied to the control conductors 23 and 24 through a variable resistance ||8 interposed in' the circuit of its eld Winding ||9.

The switchboard apparatus containing the various control devices referred to above, comprises a console |2| of the general pipe organ type having side panels |22 and |23, a stepped front panel |24, and a lower front panel |25 as shown in Figs. 4 and 5. Considering the circuit control devices in the order in which they were referred to above, the control switches 341 to 3436 are mounted on the front panels |24, Figs. and 9 and the cross connection circuit switches 391 to 39100 are mounted on the side panel |22 on opposite sides of the console and adjacent their respective pilot lamps 40 which are energized when the contacts y of the relays 261 to 2636 are closed, and which, momentarily indicate, upon momentary closure of a press button pilot etc.

lamp switch 50 on the front panel adjacent each cross connecting panel switch 341, 342, etc., what circuits are connected thereto.

Directly above the cross connecting panel switches and on the sub-panel |26 upon which they are mounted, Figs` 9 and 11, the pilot switches 5|1 to 5|3G of the control circuits are mounted. These switches are provided with the legends on and ofi and when in the ofi position, the grid conductors 22 of the circuits associated with their respective control circuits are connected directly to the negative conductor 24, as before described, and cannot be influenced by other control devices such as potentiometers, When the pilot switches 5|1 to 5|36 are in the on position, they connect the grid conductors to the single pole, double throw selector switches 521 to 5236 that are mounted on the subpanel |28 and provided with the legends pre-set and manual. When the selector switch" is in the manual position, the grid conductors of the associated circuits are connected to the movable contacts 56 of their respective control potentiometers 511 to 5136 mounted on the sub-panel |32 Figs. and 1l, and when the selector switch is in the pre-set position, the grid conductors are connected to the scene asher relays 61, 68, 69 and 10, Fig. 2 that are controlled by the scene -flasher push buttons 13 to 16, Figs. 2 and 9,

mounted on the center section of the sub-panel |28. The scene flasher relays are associated with the scene fader potentiometer 18, one for each control circuit, mounted behind the front panel |24 as will hereinafter appear.

.The scene fader is associated with movable contacts 63" to 66" of the four pre-set potentiometers 19 to 82, Figs. 2 and l1, of each control circuit, which are mounted on the sub-panel |21, Figs. 9 and 11.

The thirty-six interlocking selector switches 85, Figs. 1 and 11, are mounted upon the` panel |29, and may comprise a plurality of push buttons, for example, 86, which is shown in its depressed position. A rod |35 connected thereto carries a frusto-conical cam |36 and the two switch contacts 89 and 9|, the former of which is normally open and the latter of which is normally closed. A slide bar |31, biased toward the right by a. leaf spring |38 is provided with holes |39 of slightly larger diameter than the cam |36. As shown, button 86 is depressed and the spring |38 has so moved the bar |31 that the upper side of the cam |96 engages the bar. When any other button 81, 881, etc., is depressed, the cam |36 thereon displaces the bar toward the left as the cam |36 moves through the asf )ciated hole |39, and thereby releases the cam |36, permitting a spring |4| to return the button 86 to its original position. Thus, when any other button is depressed, the button 86 will be released, etc.

When the button 86 marked Ind for individual is depressed the grid wires of the associated circuits are controlled through the individual potentiometers 511, 512, etc.,of the control circuits.

With the button 61 depressed, the grid wires of the associated circuits are controlled through any one of the four group master potentiometers 941, 942, 943 or 94, Figs. 3, 5 and 8', mounted behind the front panel |24, as shown in Fig. 5 and adapted to be separately operated manually, through hand wheels |42, |43, |44 and |45, respectively, Figs. 4 and 8, which turn worms |46, geared to clutches |41, |46, |49 and |50, respectively, diagrammatically illustrated in Fig. 3.

The group master potentiometers 941, 942, 943 and 944 may be selectively, individually or collectively driven by a motor through magnetic clutches I5|, |52, |53 and |54, respectively, which serve to connect them to a shaft |55 that is driven by a motor |56 in a manner to be hereinafter described. Double throw group master clutch switches |511, |512, |51:I and |514, Figs. 3 and 10, marked W for hand wheel operation and M for motor operation, serve to control the ener gization of the magnet clutch and determine in what manner the group master potentiometers are to be operated, and the group master potentiometers may be selectively operated when the group master switches 981 to 9B* are in their individual position marked Ind.

The four group master potentiometers may be selectively or collectively controlled, as previously stated by a grand master potentiometer ill Figs. 3, 6 and 8, by moving such group master switches 981, 982, 963 and 98, Fig. 1, to the master position, as are desired to be controlled by the grand master potentiometer. This operation places the subvgroup potentiometers under the iniiuence of the grand master generator |05 which varies the voltage in the circuit through varying the current conditions in the eld winding of the generator.

As previously stated, the individual potentiometers 511, 511l to 513 may be grouped in groups of four each and thus selectively or collectively controlled through one of nine sub-group potentiometers |||1, |||=l to |||9 by moving the subgroup selector switches 591, 592, etc., of panel |33, Figs. 10 and 11 of desired control potentiometers, to the sub position wherein the positive ends of potentiometers 511, 512, etc., are connected through conductor ||2 to the variable contacts H31, IIB, etc., that slidably engage the sub-group potentiometers |||1, H2, etc. These sub-group potentiometers may be controlled in turn by the grand master potentiometer |0| which controls the voltage of the generator |05, by means of the subgroup potentiometer toe switches 51, H52, to |59, Figs. 1 and 4 and 5 which either connect the positive ends of the sub-group potentiometers to the positive control conductor 23 direct, or to the positive terminal of the generator |05.

A grand master potentiometer |56 is mounted for operation by the motor driven shaft |55 when connected thereto by a magnet clutch |59 and for operation by a hand wheel |6| which turns a worm |62 that drives a magnet clutch |63 which connects house master potentiometer to the hand wheel drive. The motor and hand wheel clutches |50 and |63, respectively, are controlled by a double throw switch |84 in the panel |29 having motor and wheel positions having the legends M and W, respectively.

The grand master potentiometer |0| is mounted for operation by the motor driven shaft |55 when connected, thereto by a magnet clutch |65, Figs. 3 and 8, and for operation by a grand master hand wheel |66 which turns a worm |51 that drives a magnet clutch |68 which connects the grand master potentiometer to the hand wheel drive. The motor and hand wheel clutches |65 and |46, respectively, are controlled by a double throw switch |69 having motor and wheel positions having the legends M and W, respectively.

'I'he house master potentiometer |58, group masterpotentiometers 941, 942, 943 and 944 and the grand master potentiometer |0| are adapted to be operated by means of foot pedals |121, |122,

|123, |124 and |13, respectively, pivoted on the console as indicated in Figs. 7 and 8 and con nected to the potentiometers through linkage |14 and |15 and rods |16 having loop chains |11 engaging a pinion |18 on the potentiometers; .in the usual manner. The potentiometers may be rotated in both directions by rocking the foot pedals.

The sub-group potentiometers |||1 to iii9 are adapted to be operated by pivotally mounted foot pedals |6| to |89, Figs. 4 and 5, through the medium of the linkage |9| and the rods |92 which are provided with loop chains |93 that encircle the pinions |94 which are connected to the sub-group potentiometer as previously stated, four control circuits may be selectively or collectively controlled by means of one of the subgroup potentiometers.

The scene fader potentiometers 10, thirty-six in number, are disposed on opposite sides of a scene fader drive-shaft |95, Figs. 6 and 7 that is adapted, to be connected to a motor-drive to be hereinafter described, by means of a magnet clutch |96 or to be connected to the grand master hand wheel |66 by a magnet clutch |96. Also a scene fader hand wheel |91, Figs. 4 and 8, is permanently connected to the Shaft |95 by a bevel gear |99 that is driven by a pinion 20|, and a driving rod 202 provided with universal joints 203, Figs. 6 and 8.

The scene fader potentiometers 16 are mounted in a frame 204 on the upper rear portion of the console |2|, and the movable contact arms 63, Fig. 2 of each are provided with a gear 205 that meshes with a gear 206 on the scene fader drive shaft |95 as shown in Figs. 6 and '1. Rotation of the shaft |95 causes rotation of the scene fader contact arms 83 to any desired position. When it is desired to move the scene fader contact arms at a very slow rate, the clutch |98 is energized by moving the double-throw scene fader switch 201 on the panel 208, Fig. 9, to the W or grand master hand wheel position, thus establishing a driving connection between the scene fader shaft |95 and the hand wheel |66. To drive the scene fader shaft |95 by motor, the switch 201 is moved to M position wherein the magnet clutch |96 is energized, thus connecting the shaft |95 to a motor drive to be hereinafter described.

As indicated in Figs. 6, 7 and 8, the grand master hand wheel |66 is connected to the magnet clutch |98 by means of a chain 20'9 that meshes with pinions 2|| and 2|2 on the worms |61 and 2|3 respectively, the latter meshing with a worm wheel 2|4 fixed to the clutch |96.

Referring to Figs. 5, 6, '7 and 8, the motor drive for the group and grand master potentiometer shaft |55 and the scene fader drive shaft |95 comprises a motor |56 mounted upon a base 246 of the console |2I, that drives two gears 2|1 and 2|8 at different speeds through a gear train 2|9 and 22| connected to the motor by a belt 222. For example, the gear 2|1 has a 1 to 600 ratio with the motor and is termed the highv speed gear, and the gear 2|6 has a l to 5700 ratio with the motor and is termed the low speed gear. As no claim is made to the specific form of gear train employed, the train is not illustrated in detail, nor is it more minutely described.

The high speed gear 2|1 is connected to the high speed clutch 223 by means of a chain 224 and the low speed gear 2|6 is connected to a low lated by a rotary control handle 229 on the panel |29, Fig. 10. Therefore, any desired driving speeds may be obtained for shafts |55 and |95 within certain limits.

Referring now to the motor-generator apparatus, Fig. 1, the main generator 25 and the grand master generator |05 are driven by motor 23| supplied with current from a feed circuit 232 having a main contacter switch 233 actuated by a magnet coil 234 that is energized through the medium of the starting contacter switch 235 having a magnet coil 236 connected across the positive and negative control conductors 23 and `24 respectively and controlled by a starting switch 231 that is so connected to a black-out switch 238 by a rocking-beam 239 that when one switch is closed-the other is opened. The switch 238 controls the magnet winding 239 of 'the black-out contacter switch |08, which in turn controls the circuits supplied by the generators 25 and |05. A battery 24| normally energizes the control circuits 23 and 24 and supplies current to the winding 236 for actuating the starting contactor' switch 235.l

Operation To start operation, all potentiometers and the generator rheostat ||8 may be set to effect full brilliancy, except those potentiometers of each circuit that are preset for effecting predetermined light intensities for different scenes, or those potentiometers that control circuits in which other than full brilliancy is desired.

The starting switch 231, Figs. 1 and 10, is rst moved to on position, thereby energizing the starting contactor switch 235 and causing the main contacts to close. This starts the 'motor 23|, which drives the generator 25 and |05, thus energizing the control circuits.

Assuming that it is desired to place any eight lighting circuits on a single control circuit means, for example, control No. 1,

'First- Move the selected eight circuit switches 391, 392, 396 etc., on the cross connecting panel |22 to the close position.

SeconcZ.-Momentarily press cross connecting panel push button switch 3111 for control circuit No. 1, energizing winding 29 of the multicontact relay 28, thereby closing the eight grid relays 21 of the circuits completed by the eight closed circuit switches 391 etc.

Closing of the grid relays sets or prepares circuits through cross connecting panel pilot lamps 40, so that they indicate the connected 'circuits when the pilot lamp switch 50 of control circuit No. 1 is closed momentarily.

Third- Determine whether circuits on control No. 1 are to be controlled individually by circuit No. 1, control potentiometer 511 or grand master potentiometer or one of the four group potentometers 981 to 944, or its respective subgroup potentiometer actuated by food pedals.

Fourth-If it isdetermined that the circuits are to Vbe controlled by the individual control potentiometer No. 511,

. A.-Press down the individual button 88 marked (Ind.) on the interlocking selector switch group 85.

B.-Determine whether to be operated manually or by preset.

C.-If determined to operate by preset, the selector switch 521 is moved to prese position.

D.-If determined to operate manually and indlvidually--the selector switch 521 is moved to manual position.

E.To finally complete the circuit, the pilot switch is moved to on or closed position.

If it is desired to operate manually as in paragraph D with the selector switch 521 in the manual position,

No. 1 control circuit individual potentiometer 511 may be operated and the eight selected circuits may be brought from blackout to full bright as desired by moving the movable contact 56 thereof that is connected to the grid conductor.

1f it is desired to operate by preset as in paragraph C.-

First-Set up the sliders or movable contacts 63", 64", 65" and 65" on preset potentiometers 19, 80, 8| and B2 respectively, of the No. 1 control circult, to effect the desired light intensities for the four separate scenes.

Second- To start on scene 1, the scene fader, of the No. l circuit, (mounted for motor or hand wheel operation) is turned either manually .or

by motor to the scene 1 position as indicated by preset indicator dial 242.

The indicator arm is actuated by a volt metery and a rheostat 243 having a contact arm 244, varies voltage in the meter ln accordance with the position of the feeder arm.

Third- Move selector switch 52 to preset position.

The eight selected circuits for scene will be energized in accordance with the preset slider button position on the preset potentiometers.

K The circuits may be manually varied if desired during .a scene by moving the preset slider buttons. 4

To fade or blend the lighting effect of Scene One to that set for Scene Two, manually,

(a) The scene fader hand wheel |91 which is connected to the scene fader drive shaft at all times, is rotated, or

(b) The scene selector switch 201, Figs. 3 and 9 is moved to the W or wheel position, thereby connecting the scene fader drive shaft to the grand masters hand wheel |66 by means of the magnet clutch |98.

All circuits connected to the No. control circuit will be slowly effected by movement of Ithe grand master hand wheel which turns the fader drive shaft at a slower speed than the hand wheel |91, it requiring about twelve turns of the grand master hand wheel to cause one revolution of the fader arm. Therefore, the grand master hand wheel is used to obtain very gradual changes in light intensities of the associated circuits.

The lighting circuits associated with the No. l control circuit may be influenced at this time if desired by either the preset potentiometers 19, 80, 8| and 82 or the individual potentiometer 51', depending on the position of the selector switch 52'.

To obtain motor operation of the scene fader drive shaft.-

First.-Determine the speed of scene fader operation desired, by moving 4the speed selector clutch switch 228 to the fast or slow position and a fast or slow speed will result. The fast and slow magnet clutches 223 and 225 on the shaft |55 continually operate at fast and slow speeds respectively and when energized connect the clutches to the shaft |55, depending upon the position of the scene fader. The shaft |55 is connected through sprockets and a chain 221 to the motor drive fader clutch |86, and consequently the latter clutch is driven, at a speed corresponding to that at which the shaft |55 is driven by the fast and slow clutches 223 and 225, respectively,

Second-Move scene fader switch 281 to M position which energizes the magnetic clutch |96 and connects the scene fader drive shaft to the motor drive.

Third- Move motor reversing switch 245 to F position for forward operation, or to R for reverse operation, as desired.

Fourth-Stop the scene fader by moving the scene fader selector switch to the off or vertical position, thus de-energizing the magnet clutch |96. To stop the motor, move the motor switch 245, Fig. 10, to control onneutral position.

In order to flash from one scene to another without fading through the successive scenes, and assuming that it is desired to obtain the illumination preset for scene regardless of the scene fader position- First-Press scene ilashover button No. 13 on the center of the panel |28, Fig. 9, which connects scene No. flashover relay B1 in circuit, thereby operating the relay and opening the scene fader arm by opening the fader cut-out switch 1| as previously described.

Seconds-T0 flash to any other scene press corresponding scene ilashover button 'I3 to 16 and pull out the previously closed button. The setting for the selected scene will then control the associated light circuits.

Returning now to the second above mentioned alternative method of control for the circuits associated with a control circuit, namely, control by the grand-master potentiometer,-

First.-Press down the grand master button 81 of the interlocking switch 85.

Second-Determine whether to be under preset control or individual manual control- (a) If individual control-The individual potentiometer must be set for maximum light intensity required in the circuits governed by that control circuit.

(b) If determined to operate underv preset, the preset buttons 63 to E6 for the four scenes will be preset as desired.

Third-Move pilot switch 5|, for No. control circuit on panel |25 to on position to complete setting up of that control circuit.

Fourth- Operation of the grand master potentiometer will effect all connected circuits by varying the field current of the grand master generator and thus effects the light intensity of all of the then energized circuits. The illumination will start at the brilliancy determined by presets if all of the resistance of the grand masters is out.

As the iield current is varied to reduce the voltage of the control circuit, the brilliancy will diminish correspondingly from the brilliance ini,- tially determined by the preset potentiometers.

Fifth- Since the grand-master potentiometer may be operated by foot pedal at all times, and by motor or by hand wheel, determine what method of operation is desired.

(A) If determined to operate by hand wheel, throw grand-master switch |69, panel |25, Fig. 10 to W or wheel position, thereby connecting the grand-master hand wheel to the grand-master potentiometer iii! through the magnet clutch i618, Fig. 3.

(B) if determined to operate grand-master potentiometer by the motor,

(a) Move the grand-master switch |69 to M or motor position and select speed by moving the speed selector switch 228 to the desired speed. Fast or slow, thus connecting the potentiometer shaft |55, Fig. 3, to the desired fast or slow driving clutch 223 or 225.

(b) Move the motor switch 245 to the U or upposition if it is desired to increase the intensity oi illumination or to the D or down-position if it is desired to diminish the illumination.

Sindh- To stop the grand-master potentiometer, move the grand-master switch |69 to vertical position.

Seventh- Since the grand-master potentiometer IDI is connected to a foot pedal |10 at all times, it may be actuated at will by rocking the pedal with the foot.

Referring now to` the third previously mentioned alternative method of controlling the lighting circuits associated with a control circuit, namely, by theV group-master poten-tiometers which may be operatedby hand-wheel, foot-pedal or motor. f

First-Select a group-master, say No. l and determine the manner of operation of the groupmaster potentiometer.

(A) Press down button 881 in interlocking switch 85, panel |25, Fig. 10, thereby connecting the group-master potentiometer Ito any control circuits in which No. l group-master key is pressed down.

Second-Determine whether to be under preset control or individual manual control.

(A) If individual manual control, the individual potentiometer 511 must be set for 4 maximum light intensity required in the circuits governed by that control circuit and the switch 98 is then moved to ind or independent position.

Third-If determined to operate under preset con-trol, the

(A) preset buttons B3 to 6G for the four scenes thereof will be preset as desired.

(B) Move pilot switch 5|, for No. i control circuit on panel |26 to On position to complete setting up of that control circuit. Movement of the group-master potentiometers will then cause variations in the illumination of circuits associated with the control circuits whether controlled through preset or individualmanual control.

To obtain motor operation of 'the group-master potentiometer.

(A) Determine the speed of group-master potentiometer desired, by moving the speed selector clutch switch 228 to the fast or slow position. The drive shaft |55 will be connected to the motor in the mannerl described in connection with the motor drive of the scene-fader potentiometers. 

